GRK Fasteners TOP STAR 24050 Shim Screw, 3/8 in Thread, 2-1/2 in L, Coarse Thread, Flat Head, Star Drive, Standard Point

GRK's adjustable TOP STAR shim screw, is in fact a screw within a screw that allows you to install wooden doors or windows without the use of shims. The quick and easy system reduces labor and allows for hassle free adjustment to ensure plumb installation. Our product is suited to meet the needs of both professional contractors and weekend warriors making the job easier for one person. Fine adjustments are as simple as the turn of a screw, even after years of use and settling.